Downdraft pilot for vaporizing oil burners



April 17, 1951 H. B. DoNLl-:Y

DOWNDRAFT PILOT FOR VAPORIZING OIL BURNERS Filed Feb. 24, 1948 /lllllll I I osslesfe@ fafa/a. y MM Patented Apr. 17, 1951 UNITED STATES PATENT OFFICEv DOWNDRAFT PILOTFOR VAPORIZING OIL BURNERS Harold B. Donley, Columbus, Ohio, assignor to Columbus Metal Products, Inc., Ohio, a corporation of Ohio Columbus,

Application February 24, 1948, Serial No. 10,257-

A further object is to provide a pilot light of the type indicated which is vpermanently located within the pot or main burner and which remains in place at all times.

Another object is to provide a pilot lightV through which all the fuel used in the main burner is passed in liquid or vaporized form.

Another object is to provide a pilot structure in which a substantial area of the pot bottom is maintained adequately heated.

Another object is to provide a pilot structure in which there is a minimum of smoking or carbon deposit or distillation.

Another purpose is to provide a pilot structure with a low turn down.

Other purposes will appear from time to time in the course of the specification and claims.

Figure 1 is a vertical section on the axis of the pot;

Figure 2 is a section on the line 2 2 of Figure 1;

Figure 3 is a section on the line 3-3 of Figure 1.

Like parts are indicated by like characters in the specification and drawings.

As shown, the burnercomprises an outer wall or jacket I which may be closed at its bottom by a member 2 provided with an opening 3. burner pot I is positioned within themember I and is supported on a ledge 5 fixed to the member I. A ame plate 6 may be positioned over the pot ll. This plate is provided with an opening I and may have a centering annular enlargement B. The pot 4 is provided with one or more groups or rows of perforations `ii positioned in its walls, and with a row or group of upwardly inclined perforations II) positioned toward' its upper edge. The pot A is closed by a plate or member I I which, as shown, is integral with the remainder of the member 4. The member 4 may be provided with a lateral flange I2 which rests upon the ledge 5 and beneath the flame ring B. A fuel inlet I3 is formed of a pipe or conduit which conducts fuel from any source to the interior of the pilot and thence to the interior of the pot.

The pilot structure herein shown may include a circumferential and generally cylindrical or partially cylindrical wall 2D. This wall may at 2 its ends, as at 2 I, butt against the opposed inner surface of the pot wall 4. If necessary, any suitable sealing means, not herein shown, may be used. The pilot housing or pilot piece is shown as having a closed top wall 22, upwardly formed at one point to constitute a duct 23 through which air from within the outer jacket I may pass through the aperture 24 in the pot Wall 4.

Within the pilot housing thus formed, I provide an inner top wall 25 which has a downwardly extending and general cylindrical wall 26 connecting' to the circumferential outer wall 20 by the upwardly and outwardly wall portion 21. The wall 26 does not constitute a complete cylinder but terminates at its ends with connecting walls 28 which are shown as extending to and abutting against the inner surface of the pot side wall 4. It will vbe understood that the parts above described may be connected to each other and to the pot in any suitable manner. I illustrate the pilot piece, for convenience, as formed of an inner and outer piece connected by the spacing stud 29 and the securing screw 2'9a. But this is merely an example of one method of forming and assembling the pilot piece. Nor do I wish to be limited to any particular means of or method for securing the pilot piece, as a whole, in relation to the pot.

In the use of the device, the fuel supplied for the pot is delivered along the supply duct I3. The fuel then ilows across the bottoni II of the pot.V Primary air for the mixture flows downwardly through a plurality of primary air inlets 30 which are shown as generally vertical inlets or passages in the inner horizontal wall 25. These apertures deliver air downwardly toward the bottom of the pot and into the vaporized volatile fuel. The primary mixture is preferably not completely combustible being heavily on the rich side, so far as the fuel component is concerned. This mixture iiows outwardly and moves towards the outlet openings or notches 3| formed in the lower edge of the circumferential wall 2li.

I provide secondary air supply means for the rich mixture, in the form of secondary air inlets 32 which may be conveniently formed in the wall 21 and are preferably inclined downwardly and outwardly in relation to the portion or space of the pilot piece. I find it advantageous, in some circumstances, to align the secondary air inlets 32 with the solid parts 33 of the lower edge of the wall 2D, but this is a matter of choice and need not in all cases be done.

I illustrate also an outer wall or circumferential bale 35. This may be spaced somewhat outwardly from the circumferential wall but is preferably substantially shorter than the wall 29. The baffle 35, however, may be omitted if desired.

It will be realized that the details of the pilot structure can be widely varied. For example, any suitable means may be employed for spacing or positioning the pilot piece. in relation to the pot, and for spacing the outer wall or bai-lie in relationY to the pilot piece. For example in Figure 3, I illustrate connecting wall or lugs 35, which may be used if desired, and may extend between the walls 2li and 35, or may be used, as spacers, and in that event may be secured to either the wall 2@ or the wall 35. Whereas I have described and shown a practi-iy cal and operative device, nevertheless many changes in the size, shape, number and disposition of parts may be made without departing from the spirit of my invention. I therefore wish my description'and drawings to be taken as in a broad sense illustrative or diagrammatic, rather than as' limiting me. to my precise showing.

The use and operation of my invention are as follows:

In the particular from herein shown, the pilot piece or housing is mounted within a pot type or vaporizing burner adapted for the combustion of v the wall 35 is omitted, these jets may form what is in effect a star of flame, covering a substantial part of the bottom of the pot. Under some circumstances, I nd it advantageous to provide the circumferential baffle 35 which somewhat reduces that part of the pot area over which the flame delivers, but which maintains clean and otherwise advantageous combustion conditions.

The fact that the flame passes outwardly through a plurality of apertures 3 I, formed in the lower edgev of the wall 20, makes acute sealing of vthe lower edge ofthe wall 20 in relation to the a portion overlying the. mixing chamber and a considered the primary air. It mixes with liquid fuel present in the pot and causes a primary vaporization. This results inra rich mixture which rises and into which secondary air is discharged kthrough the upwardly inclined openings or perforations I. When sufficient fuel is present, combustion occurs in the pot above the bottom, and nal combustion occurs toward the.z

bottom I I, the pot side wall-4, the inner pilot wall 25 and the circumferential pilotwalls 2t and Z'I.

Into this space, through the supply duct I3, the entire supply of fuel for they burner flows. It will be realized, however, Vthat if I desire, I may use more than one' supply duct and may, in that event,`have some main fuel supply means other than the duct which suppliesv the pilot piece.

The liquid fuel, which is delivered at various volumes by any suitable controlV means not herein shown, such as a conventional'fl'oat valve, fows open and is evaporated upon the bottomv of the pot. I nd it advantageous to direct the primary air supply directly downwardly into the space X and against the mixture burning therein. At minimum rates of flow the combustion may take place solely within the space X, but I find it Vpreferable to maintain a fuel flow, even during pilot use, effective to cause the movement of jets of flame outwardly through theV notches or openings 3 I, and along the bottom of the pot. Where second portion surrounding an upper, inner part of the mixing chamber, said surrounding portion extending substantially downwardly and terminating' adjacent but above the bottom of the pot, said pilot structure having an air inlet to said plenum chamber registeringv with an opening in the side wall of said pot and adapted'to receive an air supply therethrough, the pilot structure having a plurality of flame outlets located in the llower edge of said mixing chamber, that wall portion of the pilot structure which denes the bottom of the surrounding portion of the plenum chamber having therein secondary air inlet apertures adapted to direct downward jets of air adjacent said flame outlets, that portion of the pilot structure wall separating the upper, inner part of the mixing'chamber from the overlying portion of the plenum chamber having primary air inlet apertures therein adapted for the direction of air downwardly into the mixing chamber at points remote from the flame outlet.

2. The structure of claim 1 characterized by and including the provision of the secondary air inlet apertures in staggered relation with the ame outlets about the lower edge of the pilot structure.

3. The structure of claim 1 characterized by and including an exterior baffle upwardly extending from the bottom of the burner pot, and means for positioning it closely about thepilot structure and substantially normal tothe axis of the flame outlets.

`-HAROLD B. DONLEY.

REFERENCES CITED The following references are of record' in the fllc of this patent:l

UNITED STATES PATENTS Great Britain. Jan. 25, 1938 

